Morphological characterization of the hemocytes of the clam, Ruditapes decussatus (Mollusca: Bivalvia).

Hemocytes play an important role in internal defence in molluscs. The morphology of hemolymph cells was studied for the first time in Ruditapes decussatus. Two main types of hemocytes (hyalinocytes and granulocytes) exist in R. decussatus. Three types of granulocytes were identified by light microscopy, in accordance with the presence of basophilic or acidophilic granules or a mixture of both in the cytoplasm. The existence of hyalinocytes and granulocytes was confirmed by electron microscopy. Some monoclonal antibodies (MABs) raised against hemocytes of Crassostrea gigas showed cross-reactivity with the total population of hemocytes of R. decussatus; however, none of the MABs raised against hemocytes of Mytilus edulis showed cross-reactivity. The MABs assayed did not allow us to distinguish hemocyte subpopulations.